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From: Ming Lei <ming.lei@redhat.com>
To: Daniel Wagner <dwagner@suse.de>
Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
	James Smart <james.smart@broadcom.com>,
	Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
	Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH 2/2] nvme-fc: Wait with a timeout for queue to freeze
Date: Tue, 29 Jun 2021 09:39:30 +0800	[thread overview]
Message-ID: <YNp50pmlzN6M0kNX@T590> (raw)
In-Reply-To: <20210625101649.49296-3-dwagner@suse.de>

On Fri, Jun 25, 2021 at 12:16:49PM +0200, Daniel Wagner wrote:
> Do not wait indifinitly for all queues to freeze. Instead use a
> timeout and abort the operation if we get stuck.
> 
> Signed-off-by: Daniel Wagner <dwagner@suse.de>
> ---
>  drivers/nvme/host/fc.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index a9645cd89eca..d8db85aa5417 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -2955,7 +2955,14 @@ nvme_fc_recreate_io_queues(struct nvme_fc_ctrl *ctrl)
>  		dev_info(ctrl->ctrl.device,
>  			"reconnect: revising io queue count from %d to %d\n",
>  			prior_ioq_cnt, nr_io_queues);
> -		nvme_wait_freeze(&ctrl->ctrl);
> +		if (!nvme_wait_freeze_timeout(&ctrl->ctrl, NVME_IO_TIMEOUT)) {
> +			/*
> +			 * If we timed out waiting for freeze we are likely to
> +			 * be stuck.  Fail the controller initialization just
> +			 * to be safe.
> +			 */
> +			return -ENODEV;
> +		}
>  		blk_mq_update_nr_hw_queues(&ctrl->tag_set, nr_io_queues);
>  		nvme_unfreeze(&ctrl->ctrl);

Can you investigate a bit on why there is the hang? FC shouldn't use
managed IRQ, so the interrupt won't be shutdown.

blk-mq debugfs may help to dump the requests after the hang is triggered,
or you still can add debug code in nvme_wait_freeze_timeout() to dump
all requests if blk-mq debugfs doesn't work.


Thanks,
Ming


_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

WARNING: multiple messages have this Message-ID (diff)
From: Ming Lei <ming.lei@redhat.com>
To: Daniel Wagner <dwagner@suse.de>
Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
	James Smart <james.smart@broadcom.com>,
	Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
	Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH 2/2] nvme-fc: Wait with a timeout for queue to freeze
Date: Tue, 29 Jun 2021 09:39:30 +0800	[thread overview]
Message-ID: <YNp50pmlzN6M0kNX@T590> (raw)
In-Reply-To: <20210625101649.49296-3-dwagner@suse.de>

On Fri, Jun 25, 2021 at 12:16:49PM +0200, Daniel Wagner wrote:
> Do not wait indifinitly for all queues to freeze. Instead use a
> timeout and abort the operation if we get stuck.
> 
> Signed-off-by: Daniel Wagner <dwagner@suse.de>
> ---
>  drivers/nvme/host/fc.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index a9645cd89eca..d8db85aa5417 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -2955,7 +2955,14 @@ nvme_fc_recreate_io_queues(struct nvme_fc_ctrl *ctrl)
>  		dev_info(ctrl->ctrl.device,
>  			"reconnect: revising io queue count from %d to %d\n",
>  			prior_ioq_cnt, nr_io_queues);
> -		nvme_wait_freeze(&ctrl->ctrl);
> +		if (!nvme_wait_freeze_timeout(&ctrl->ctrl, NVME_IO_TIMEOUT)) {
> +			/*
> +			 * If we timed out waiting for freeze we are likely to
> +			 * be stuck.  Fail the controller initialization just
> +			 * to be safe.
> +			 */
> +			return -ENODEV;
> +		}
>  		blk_mq_update_nr_hw_queues(&ctrl->tag_set, nr_io_queues);
>  		nvme_unfreeze(&ctrl->ctrl);

Can you investigate a bit on why there is the hang? FC shouldn't use
managed IRQ, so the interrupt won't be shutdown.

blk-mq debugfs may help to dump the requests after the hang is triggered,
or you still can add debug code in nvme_wait_freeze_timeout() to dump
all requests if blk-mq debugfs doesn't work.


Thanks,
Ming


  parent reply	other threads:[~2021-06-29  1:40 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-25 10:16 [PATCH 0/2] Handle update hardware queues and queue freeze more carefully Daniel Wagner
2021-06-25 10:16 ` Daniel Wagner
2021-06-25 10:16 ` [PATCH 1/2] nvme-fc: Update hardware queues before using them Daniel Wagner
2021-06-25 10:16   ` Daniel Wagner
2021-06-27 13:47   ` James Smart
2021-06-27 13:47     ` James Smart
2021-06-29  1:32   ` Ming Lei
2021-06-29  1:32     ` Ming Lei
2021-06-29 12:31   ` Hannes Reinecke
2021-06-29 12:31     ` Hannes Reinecke
2021-06-25 10:16 ` [PATCH 2/2] nvme-fc: Wait with a timeout for queue to freeze Daniel Wagner
2021-06-25 10:16   ` Daniel Wagner
2021-06-27 14:04   ` James Smart
2021-06-27 14:04     ` James Smart
2021-06-29  1:39   ` Ming Lei [this message]
2021-06-29  1:39     ` Ming Lei
2021-06-29  7:48     ` Daniel Wagner
2021-06-29  7:48       ` Daniel Wagner
2021-07-05 16:34     ` Daniel Wagner
2021-07-05 16:34       ` Daniel Wagner
2021-07-06  7:29       ` Ming Lei
2021-07-06  7:29         ` Ming Lei
2021-07-06  8:10         ` Daniel Wagner
2021-07-06  8:10           ` Daniel Wagner
2021-07-06  8:45           ` Ming Lei
2021-07-06  8:45             ` Ming Lei
2021-07-06  8:59             ` Daniel Wagner
2021-07-06  8:59               ` Daniel Wagner
2021-07-06 12:21               ` Daniel Wagner
2021-07-06 12:21                 ` Daniel Wagner
2021-07-07  2:46                 ` Ming Lei
2021-07-07  2:46                   ` Ming Lei
2021-06-29 12:31   ` Hannes Reinecke
2021-06-29 12:31     ` Hannes Reinecke
2021-06-25 12:21 ` [PATCH 0/2] Handle update hardware queues and queue freeze more carefully Daniel Wagner
2021-06-25 12:21   ` Daniel Wagner
2021-06-25 13:00   ` Ming Lei
2021-06-25 13:00     ` Ming Lei
2021-06-29  1:31     ` Ming Lei
2021-06-29  1:31       ` Ming Lei

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